Born and raised in Gwangju, South Korea, Yunho started his musical training under the talent agency SM Entertainment in 2001 and joined TVXQ in 2003 as the band's leader.

[citation needed] To provide for himself while he trained in Seoul, Yunho took up various part-time jobs in the city, such as doing snow removal in the morning and working as a waiter at night.

[citation needed] Sometime later, Yunho suffered a hormonal imbalance in his throat and underwent surgery, which affected his vocal cords.

In late 2001, at the age of fifteen, Yunho was featured as a rapper and backup dancer in Dana's debut single "Diamond", and briefly toured with her.

[7] The final line-up of TVXQ consisted of Yunho, Max Changmin, Jaejoong, Park Yoo-chun, and Kim Jun-su.

Their fourth Japanese album The Secret Code spawned two platinum-selling singles "Dōshite Kimi o Suki ni Natte Shimattandarō?"

TVXQ was plunged into legal turmoil when members Jaejoong, Yoochun, and Junsu filed an injunction against their Korean agency in July 2009.

[8] Consisting of seven tracks, the mini album includes five songs that were previously performed by Yunho during TVXQ's concerts and solo events in Japan.

Bundled with a DVD that includes a music video and behind-the-scenes footage, U Know Y received a limited release, and was only made available for purchase to members of TVXQ's Japanese fanclub, Bigeast.

Yunho's debut extended play, True Colors, was announced on May 28 and was released on June 12 alongside its lead single "Follow".

[15] On August 7, 2023, Yunho will release his third korean extended play Reality Show, alongside its lead single "Vuja De".

He appeared in the MBC sitcom Nonstop 4, and participated in the television drama Vacation and movie Dating on Earth starring all of the members of TVXQ.

[17] Yunho made his official acting debut in 2009, playing the male lead in romantic comedy series Heading to the Ground.

[20] From November 2012 to January 2013, Yunho starred in his second musical Gwanghwamun Sonata, a story set in South Korea during the democratic movement in the 1980s.

[24][25] Yunho was widely praised for his acting, managing fierce action scenes and effectively portraying the delicate emotions of his character.

[citation needed] While TVXQ was filming a variety show on October 14, 2006, Yunho was rushed to the hospital after drinking a beverage laced with super glue, given to him by an anti-fan.

[45][46] On March 7, 2022, Yunho donated 50 million won to the Community Chest of Korea for Fruit of Love to help the victims of the massive wildfire that started in Uljin, Gyeongbuk and has spread to Samcheok, Gangwon.